The Regency era of British history is commonly described as the years between c. 1795 and 1837, although the official regency for which it is named only spanned the years 1811 to 1820. King George III first suffered debilitating illness in the late 1780s, and relapsed into his final mental illness in 1810; by the Regency Act 1811, his eldest son George, Prince of Wales, was appointed prince regent to discharge royal functions. When George III died in 1820, the Prince Regent succeeded him as George IV. In terms of periodisation, the longer timespan is roughly the final third of the Georgian era (1714–1837), encompassing the last 25 years or so of George III's reign, including the official Regency, and the complete reigns of both George IV and his brother and successor William IV. It ends with the accession of Queen Victoria in June 1837 and is followed by the Victorian era (1837–1901).

In a monarchy, a regent is a person appointed to govern a state pro tempore because the actual monarch is a minor, absent, incapacitated or unable to discharge their powers and duties, or the throne is vacant and a new monarch has not yet been determined. One variation is in the Monarchy of Liechtenstein, where the competent Prince may choose to assign regency to their of-age heir, handing over the majority of their responsibilities to prepare the heir for succession. The rule of a regent or regents is called a regency. A regent or regency council may be formed ad hoc or in accordance with a constitutional rule. Regent is sometimes a formal title granted to a monarch's most trusted advisor or personal assistant. If the regent is holding the position due to their being in the line of succession, the compound term prince regent is often used; if the regent of a minor is their mother, and she is wife or widow of the king, she would be referred to as queen regent.